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linux-next/include/asm-generic/bitops/instrumented-lock.h
Daniel Axtens 81d2c6f819 kasan: support instrumented bitops combined with generic bitops
Currently bitops-instrumented.h assumes that the architecture provides
atomic, non-atomic and locking bitops (e.g. both set_bit and __set_bit).
This is true on x86 and s390, but is not always true: there is a
generic bitops/non-atomic.h header that provides generic non-atomic
operations, and also a generic bitops/lock.h for locking operations.

powerpc uses the generic non-atomic version, so it does not have it's
own e.g. __set_bit that could be renamed arch___set_bit.

Split up bitops-instrumented.h to mirror the atomic/non-atomic/lock
split. This allows arches to only include the headers where they
have arch-specific versions to rename. Update x86 and s390.

(The generic operations are automatically instrumented because they're
written in C, not asm.)

Suggested-by: Christophe Leroy <christophe.leroy@c-s.fr>
Reviewed-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Daniel Axtens <dja@axtens.net>
Acked-by: Marco Elver <elver@google.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20190820024941.12640-1-dja@axtens.net
2019-11-07 13:15:39 +11:00

82 lines
2.5 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
/*
* This file provides wrappers with sanitizer instrumentation for bit
* locking operations.
*
* To use this functionality, an arch's bitops.h file needs to define each of
* the below bit operations with an arch_ prefix (e.g. arch_set_bit(),
* arch___set_bit(), etc.).
*/
#ifndef _ASM_GENERIC_BITOPS_INSTRUMENTED_LOCK_H
#define _ASM_GENERIC_BITOPS_INSTRUMENTED_LOCK_H
#include <linux/kasan-checks.h>
/**
* clear_bit_unlock - Clear a bit in memory, for unlock
* @nr: the bit to set
* @addr: the address to start counting from
*
* This operation is atomic and provides release barrier semantics.
*/
static inline void clear_bit_unlock(long nr, volatile unsigned long *addr)
{
kasan_check_write(addr + BIT_WORD(nr), sizeof(long));
arch_clear_bit_unlock(nr, addr);
}
/**
* __clear_bit_unlock - Clears a bit in memory
* @nr: Bit to clear
* @addr: Address to start counting from
*
* This is a non-atomic operation but implies a release barrier before the
* memory operation. It can be used for an unlock if no other CPUs can
* concurrently modify other bits in the word.
*/
static inline void __clear_bit_unlock(long nr, volatile unsigned long *addr)
{
kasan_check_write(addr + BIT_WORD(nr), sizeof(long));
arch___clear_bit_unlock(nr, addr);
}
/**
* test_and_set_bit_lock - Set a bit and return its old value, for lock
* @nr: Bit to set
* @addr: Address to count from
*
* This operation is atomic and provides acquire barrier semantics if
* the returned value is 0.
* It can be used to implement bit locks.
*/
static inline bool test_and_set_bit_lock(long nr, volatile unsigned long *addr)
{
kasan_check_write(addr + BIT_WORD(nr), sizeof(long));
return arch_test_and_set_bit_lock(nr, addr);
}
#if defined(arch_clear_bit_unlock_is_negative_byte)
/**
* clear_bit_unlock_is_negative_byte - Clear a bit in memory and test if bottom
* byte is negative, for unlock.
* @nr: the bit to clear
* @addr: the address to start counting from
*
* This operation is atomic and provides release barrier semantics.
*
* This is a bit of a one-trick-pony for the filemap code, which clears
* PG_locked and tests PG_waiters,
*/
static inline bool
clear_bit_unlock_is_negative_byte(long nr, volatile unsigned long *addr)
{
kasan_check_write(addr + BIT_WORD(nr), sizeof(long));
return arch_clear_bit_unlock_is_negative_byte(nr, addr);
}
/* Let everybody know we have it. */
#define clear_bit_unlock_is_negative_byte clear_bit_unlock_is_negative_byte
#endif
#endif /* _ASM_GENERIC_BITOPS_INSTRUMENTED_LOCK_H */